Chapter 5 Flashcards
Passive transport
movement of substances across a cell’s membrane without expenditure of energy
Diffusion
Net movement of substances from regions of high concentration to regions of lower concentration
Facilitated diffusion
diffusion of molecules or ions through carrier proteins or ion channels
Channel proteins
Carrier proteins
Membrane protein that binds to a molecule that cannot cross the membrane
Ion channels
Membrane proteins that allow passage of ions through phospholipid bilayer
Gated channels
Channel proteins that can be opened or closed in response to a stimulus
______ ________ is diffusion facilitated by membrane proteins.
Facilitated diffusion
Facilitated diffusion requires a ________ _______.
Concentration gradient
Aqueous solution
Water-based solution
Osmosis
Net diffusion of water across a membrane toward a higher solute concentration
Osmosis and diffusion are the same except osmosis involves _______.
Water
Concentration of all solutes in a solution determines the _______ ________.
Osmotic concentration
Hypertonic
Solution with higher concentration of solutes than the cell
Hypotonic
Solution with lower concentration of solutes than the cell
Isotonic
Solution having the same concentration of solutes as the fell
What happens to a cell in a hypotonic solution?
• Cytoplasm is hypertonic relative to extracellular fluid
• Water diffuses into cell —> cell swells
• Increases pressure of cytoplasm pushing on cell membrane
Aquaporin
Membrane channel that allows water to cross the membrane more easily
Osmotic pressure
Force needed to stop osmotic flow
T or F: Active transport requires energy expenditure
True
Sodium-potassium pump runs ______ on ATP.
Directly
Cells use the Na+/K+ pump to create a high concentration of Na+ _______ the cell, and a high concentration of K+ _______ the cell.
Outside; inside
Coupled transport uses ATP ________.
Indirectly
Coupled transport
Uses energy releases as one molecule moves DOWN its concentration gradient to move a different molecule UP its gradient
In _________, the plasma membrane envelops food particles and fluids
Endocytosis
Endocytosis
Uptake of material into cells
Three types of endocytosis:
- Phagocytosis
- Pinocytosis
- Receptor-mediated endocytosis
T or F: Endocytosis requires energy expenditure
True
Phagocytosis
Uptake of a solid particle
Pinocytosis
Process of fluid uptake
Receptor-mediated endocytosis
Molecules bind to specific receptors in the plasma membrane
Exocytosis
Discharge of material from vesicles at cell surface
In plant cells, exocytosis is often used to…
Transport materials to build cell walls
In animal cells, exocytosis is used to…
Secrete hormones, neurotransmitters, and digestive enzymes
Channel proteins have a ________ interior.
Hydrophilic
Ion channels have a _____ interior that spans the membrane.
Hydrated (polar)
Rate of diffusion is limited by…
- Concentration gradient (how concentrated solutes are)
- Number of available carrier proteins
Water diffuses OUT of a cell in a _______ solution.
Hypertonic
In a hypertonic solution, the cytoplasm is _______ relative to extracellular fluid.
Hypotonic
In coupled transport, glucose is brought ____ the fell with _____.
Into; Na+
In ______ ________, molecules are moved against their concentration gradient by using the energy stored in a gradient of a different molecule.
Coupled transport
In ______ ________, molecules are moved against their concentration gradient by using the energy stored in a gradient of a different molecule.
Coupled transport
In ___________, fluid droplets are engulfed by membrane, which forms vesicles around them
Pinocytosis
___________ is a type of endocytosis triggered by a specific receptor, forming clathrin-coated vesicles
Receptor-mediated endocytosis
